Improved valve-gear for steam-engines



UNITED STATES PATENT EEICE.

i. w. BOwERs, OE CINCINNATI, OHIO.

IMPROVED VALVE-GEAR FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 43,757, dated August 9,1864.; antedated January 27, 1864.

To all whom t may concern:

Be it known that l, I. W. BOWERS, of Cincinnati, in the county ofHamilton and State ot' Ohio, have invented certain new and usefulImprovements in Steam-Engines; and I do hereby declare the following tobe a full, clear, and exact description of the same, reference being hadto the accompanying drawings and letters of reference marked thereon,forming part of this specification.

My invention relates to the valve-chamber and mode of operating thevalves, also to a variable or adjustable cut-oft'.

In the accompanying sheet of' drawings, Figure l is a perspective viewvof a horizontal high-pressure engine, in which my improvements arepresented. Fig. 2 is a side elevation of the same. Fig. 3 is an enlargedrepresentation of the parts by which the valves are Operated. Fig. et isa transverse section of the valve-chamber. Fig. 5 is a vertical sectionof the same. Fig. 6 is a horizontal section of the T or cross head andslides.

In the following description like letters ot' reference indicatecorresponding parts in the different drawings.

A is the bed-plate of the engine. B is the cylinder. C is thecross-head. D is the pitman 5 F, the cam or eccentric, and F the camrod.G G are ingress-valve chambers. G G are exhaust-valve chambers.

The valve-chambers are made, as represented, Ot' considerabledimensions, and conp tain the lifting-arm by which the valve isactuated, the valve-stem being also contained entirely in the chamber.

Figs. 4 and 5 are enlarged representations of the valve-chambers. Asthese are all alike in construction and in the arrangement for operatingthe valves, the description of one will be understood as applying toall.

i is the valve-seat; H, the valve-stem. Through an enlargement below thestem, which may be termed the body 7 ofthe valve, inortises lare madeatright angles to each other, of considerable length vertically, in whichthe rods m and the lit'tersu are arranged to operate, the mortises beinglong enough to allow the valve to raise and fall without interference.

o is a projecting piece secured to the valve kat an appropriate point toreceive the action of the lifter n, by which the valve is raised oropened. The rod on, which carries the lifter and operates j the valve,enters the valvechamber through a stuffing-box, p, and on its outer endreceives a crank, m.

Referring now to the upper or ingress valve chambers, and to the partsappertaining thereto, it will be seen that the cranks m fm' areconnected by a bar, q, so that when' this bar is operated or caused tovibrate, as will presently arpear, the cranks and rods to which it isapplied arc simultaneously vibrated.

Depending from the two cranks m m are rods m m, which carry weights m m,and these by their gravity tend to hold or return the cranks to avertical position, in which position both valves are closed. Now, thearran gement of these parts is such that when the connectingbar q isvibrated from a central position in one direction it operates throughthe appropriate crank-rod and lifter to open one of the valves and admitsteam to one end of the cylinder,and when released it suddenly returns`by the gravity of the weights above described to its central position,releasing the valve and allowing it to fall to its seat and out off thesteam, and when vibrated in an opposite direction a corresponding effecttakes place with the valve at the other end ot' the cylinder. It'

the vibration of the connecting-rod is arrested at a short distance froma central position the valve'will be but slightly opened, and remainopen but for a comparatively brief time, while if the vibration isgreater and prolonged-say during the time the piston is traversing thewhole length of the cylinder-the valve will be held open during thattime and the engine will be working steam at what is termed full stroke.Carried bythe connecting-bar q are two pawls, r r, pivoted as shown at ss, having abutting faces set in opposite direcltions and projecting ashort distance below the lower face of q.

K is a vibrating bar pivoted at tand caused to vibrate regularly in avertical plane through a short arc by the cam F, through the cam-rod F',the latter being connected with K by a wrist. (N not represented in thedrawings.) Upon the outer face ot' K is an adjustable or sliding bar, L,the upper end Ot' which is armed with two catches, u, faced in oppositedirections, and adapted to the faces of the pawls r r, re-

spectively. Let it be observed that the faces ot' the catches u formsurfaces of contact with the faces of paWls 1", one pair being engagedwhen the bar K is vibrated in one direction and the other pair bein-gengaged when the bar is vibrated in the opposite direction.v Let it alsobe noticed that the pawls 1' and the catches u vibrate in arcs Whosecurvatures are in opposite directions; hence as the bar q is caused tovibrate by the contact of either of said catches u with either ot' saidpaWls r, the surface of contact gradually diminishes as the respectivearcs are traversed until the paWl which is at the time engaged becomesreleased, and the bar q is permitted to return, which it does suddenly,to its central position. It vvill now be apparent that the degree ot'Vvibration communicated to the bar q, and consequently the degree andcomparative duration of the opening ot' the valves for the admission ot'steam to the cylinder, will be determined by the position of the catchesu relatively to the pawls r-that is, by raising the adjustable bar L sothat the catches have a longer hold upon the paWls, a longer vibrationwill be communicated to the connecting-bar q, even to the extcnt, aswill be readily u1:- derstood, of Working the steam full-stroke, whileby lowering the adjustable bar L until the catches have but a slighthold upon the pawls, a shorter vibration Will be communicated to theconnecting-bar, and -a correspondingly less opening will be given tothe-valves. The bar L may be set and secured in' an ap propriate mannerin any required position relatively to the connecting-bar q, so that theformer may be acted upon and caused to vibrate through a greater or lessarc, causing the valves for the ingress of steam to thecylinder to cutot't77 'steam at any desired point in the stroke of the engine; and thisadjustment of the bar L may, for greater convenv ience, be ei'ected by atemper-screw, so applied that by rotati ngit in one direction the bar Lwill be elevated and a greater opening communicated to the valves, andby rotating it in another direction the opening Will be diminished andthe admission ofsteam to the cylinder at each stroke be correspondinglyless.

It is apparent that by leaving the sliding bar L free to rise and fall,and then connecting itwith an ordinary governor, its position will beaccurately controlled thereby, and the motion of the engine governed bythis means. An arrangement for this purpose is represented in Fig. 2,whereX represents an ordinary governor; Y and Z, rods through which thegovernor acts upon the sliding bar L.

The exhaust-valves in the valve-chambers Gr G are operated by the pitmenv a, which are pivoted to vibrating bar K, as represented, and operatethrough cranks m m' upon valverods m m. The internal arrangementot thevalve-chambers and the construction and operation of the valves are inall respects similar to the ingress valves and appurtenances which havebeen described.

In the operation ofthe engine thc exhaustvalves are opened alternately,and remain open during the entire half-stroke to which the respectiveopening is appropriate.

Having fully described my invention, what I claim as new, and desire tosecure `by Letters Patent, is the following:

y l. Operating the valves H by the lifters or their equivalents, whenthey' are arranged within the valve-chamber, as shown, and for thepurpose described.

2.l The combination ot' the valves H, rockshaft m, and cranks m With theWeights m", substantially as described, and for the purpose set forth.

3. The several devices in combination by which the port or steam valvesand the exhaust or` outlet valves are operated, when -combinedsubstantiallyas described, and for the purpose set fort-h.

4. The combination of the forked sliding bar L with the vibrating bar Kand cam-rod D, when constructed and arranged substantially as described.i

5. The combination and arrangement of the connecting-bar q and pawls r rWith the cranks m' m', when constructtd substantially as described, andfor the purpose set forth.

'1. W. Bovvnns,u

VVituess: 4

W. K. NIKON, M. GREENWOOD.

